Centralized traffic control system



1934- D. w. MERSEREAU El AL. 1,959,090

CENTRALIZED TRAFFIC CONTROL SYSTEM Filed Dec. 50. 1930 05m E E EQEEF mvag? TORNEY Fatented Aug. '7, i934 UNITED STATES PATENT @FFlSE CENTRALIZED TRAFFIC CONTROL SYSTEM Donald W. Merserean and Ernest B. Kempster,

313, Rochester, N. IL, assignors to General Railway Signal Company, Rochester, N. Y.

Application December 30, 1930, Serial No. 505,490

3 Claims.

i cate one condition of traffic at said trafiic controlling device in accordance with the integrity of said circuit at said distant traffic controlling device, and in transmitting another and distinctive continuing indication from said distant trafric lscontrolling device to said central office by the application of alternating current to the same circuit at said distant trafiic controling device.

Other objects, purposes and characteristic features of the invention will in part be apparent,

" from the drawing and will in part be more specifically pointed out hereinafter.

In describing the invention in detail reference will be made to the single drawing illustrating conventionally one embodiment of the invention.

Referring to the drawing the rails l of the railway system have been shown divided into track circuited blocks by insulating joints 2, of which the detector track circuit includesa detector track relay DT and a battery 3, and the '30 block in the single track section 0 includes a track relay T and track battery 4. The switch S is preferably controlled by a switch machine SM. and governs the movement of traflic out of thesingle track section 0 into the main track '35 or the side track of said passing siding PS. The particular track lay-out illustrated may comprise part of a double track railroad, or a portion of a single track railroad equipped with absolutepermissive-block signalling. Proceeding on the assumption that the latter type of system has been illustrated, the starting signals '7 and 7 govern the movement of trains from the main track and side track of the passing siding, respectively, into the single track sectionO, whereas 'the main signal 8 and the take-siding signal 8 govern the movement of traffic from the single track section 0 into the two tracks of passing siding PS. The switch machine SM is preferably controlled by the polar control relay Z, which relay in turn is controlled by the lever L located at the central oifice DO through the medium of the line wire 10. In the central ofiice DO there is included in series with the line wire 10 an indicating relay IR the function of which is more In the central ofiice there is also provided a direct current indicating relay 1R connected to the rectifier RE, which rectifier in turn is connected to the secondary winding of the transformer TR. The indicating relay IR controls the indicating lamp I, whereas the indicating relay 1R controls the indicating lamp I Having now described the essential elements of the system it is believed expedient to consider the operation of the system and how indications of traffic conditions may be transmitted to the central office DO.

Operation Let us first assume that there is a west bound train on the main track of the passing siding PS, and that the operator wishes this train to proceed into the single track section 0. The operator will first move his lever L to the right hand position corresponding to the main track position for the switch machine SM. Movement of the lever L into the right hand dotted position will close the following circuit for energizing the polar control relay Zz-beginning at the terminal of the battery 12, wire 13, lever L, wires 14 and 15, winding of the relay IR, wires 16 and 10, primary winding of the transformer 17, wires 18 and 19, winding of the relay Z, wire 20, front contact 21 of the detector track relay D'I, wires 22 and 23, to the common return wire C connected through the medium'of wires 24 and 25 to the midpoint of the battery 12. The completion of the circuit just traced will energize the controlrelay Z to the right, but since the switch machine SM already is in the main track position the switch machine SM will not respond to the energization of the relay Z. The energization of the circuit just traced will, however, energize the indicating relay IR, thereby opening the back contact 26 of this relay IR and prevent illumination of the indicating lamp I in spite of the fact that its energizing circuit has been closed at the lever contact 27. The lever contact L is preferably so constructed, as shown by the elongated stationary contacts, that it makes its connection earlier than does the contact 2? upon movement from the middle position, this to avoid flashing of the lamp I by reason of the time required for relay IR to pick up its contact 26. The operator will then through suitable means, for convenience omitted from the drawing, allow clearance of the. starting signal '7 in accordance with traific conditions in advance, which are assumed to now be favorable, so that the signal 7 assumes its clear proceed position.

suitable battery, wire 30, lever contact 27, wire 31, back contact 26 of the relay IR, wire 32, indicating lamp 1, to battery. t V

As the train in question proceeds alittlefurther in a ivestwardly direction it'tr'eads u onthe first track circuit in the single track section 0, thereby efiecting deenergization of the track relay T and effecting closure of the'cont'act 3'4 of the relay T, thereby energizing the transformer 17 by alternating current derived from the transmission line 35'.- In response "to this energi'zation of the transformer 17 alternating current will fiow through the following circuitz beginning at the secondary winding of the transformer-l7, line wire, 10, wire 36; condenser 37, primary winding of the" transformer wires, 38 and-14 leverTL, wire 13;

one portion of this split, battery 12, wires '25 an'cl 24, common return wire C, wire 23 inductanceg 39, condenser 40, wire 18, backto the secondary winding of transformer 1:7. vIt is desired to point out at this: time that the inductance of the transformer TR and the capacity of the condenser' ii'l are of such value that when connected in series, as shown, they comprisea tuned unit tuned to resonate at the fre quency of the alternatingcurrent supplied by the transmission line 35, andsimilarly, the inductance 39 and the condenserO-are tunedto resonate for:

circuit just' traced in spite of the opening ofthe,

contact 21 of the detector track relay DT, and also the indicating relay 'IR'will furnish sufiicient impedance toallow verylittle alternating, currentto flow therethrough. I

With the transformer TR now energized; clue to the alternating current flowing by reason of the occupancy of; thQblock containing. the track relay T, direct; current is caused to flow through the winding of the indicating-relay 1R through the mediumof the rec-c tifier ,RR (preferably-ofthe multiple plate copper oxide type), the functioning of which is thor oughly understood by those skilledin the art; of

railway signalling. Obviously, the indicating lamp I is again extinguished-assoon as the trackrelay DT picks up, and similarly, the indicating lamp I which was illuminatedthrough the frontcontact 41 of relay IE is extinguished as soon as the track relay T picks-up,-

Attention is directedto the fact thatthe control relay Z-willremain deenergized so long as the contact 21 of the detector track relay DT is open,

but this is immaterialin that the switch machine SM should not be permitted to have'its operation initiated when there'is a train' occupying the detector track circuit containing track relay D'IL Obviously, movement-of the leverL-to its: left hand position will energize the relay Z to its left hand position, thereby operating the switch ma- 3 chine SM to' its reversed take-siding position through the medium of the reverse wireRr, in the same way as the switch machine SM may be operated to thenormal position through the me,-:

dium ot the normal-wire N. Obviously, the prog.-- ress of a train moving off of a side trackiofithe;

I- is-the first one to be energized. Also, instead of 1 the other terminal of said" employing the superimposed alternating current I 1 for indicating the condition of occupancy for the block containing the track relay T, this alternating cur-rent apparatus'may be employed for indicatingthe condition of occupancy of other track circuits, the position of signals, derails, or the like;

Having thus shown and described one'rather specific embodiment of the present invention it is I desired tevb'e understood that this: has been done. for the, purpose of facilitating descriptionof its underlying principles and advantageousfeatures, and has not beenselected'for the purpose-of show- F ing the scope of the invention or the exact-com; 100 struction preferably employedin' practicing the same, and that various changes, modifications and; additions maybe made to adapt the-invention to, the: particular problem encountered in practicing theisame; all without departing from thespirit or scopevof'the inventionzonthe idea of means--: underlying'the same, except as: demanded bythe scopeof the following claims.- 7

What we claimzas new is:- s.

l; a traflic controlling system, the combine-i tiontwith adistant trafilc controllingdevice of a: local central ofii'c'e; asourcei -of direct-current at said office; a circuit connecting-said oilice and said distant: trafilccontrolling device for control-t 1mg: said device through' the medium of seismic, Q 1

source, a firstdirectcurrent relay at said ofil'ce: included-"in sai'd circuit,-v a; transformer bridged across "said relay; a second direct current rela'y,,; arectifien connected to rectify alternating currentsupplied by said transformer and apply the'rectifie'd urrent to: saidsecond relay, a'controlrelay at said traffic controlling device included'in said circuit, means for energizing said circuit from said source at -said crate to control said commit relayanormally closed traific controlled 'contact l25, L

adjacent said control'relay in saijdicircultopened: under certain trafilc conditions to effect: de'energi'z'ation ofsaidnrstrelay,afilter-permittingthe flow'of alternating current bridgingsaid centrol relay and contact,- and means for introducihglm' alternatingcurrent'into said:circuit at saidtrafficii controlling device under other trafi 'c conditions; to effect energizationof said second: relay;

2. In atraifi'c controlling'sy'stem the combina tionwith a distant name con-trolling device, :or a A local central office, a source of direct current at' saidofiice, a circuit connecting said 'ofiice and; said distant trafliccontrollihgideviceforcontrolj ling-said device through the meuium of said source, a first direct current relayat said o'fli'ce' includedin said a transformer bridged across said relay;- asecond relay energized from s'aid transformer, a control relay ati'sai'd tra-mc controlling device" included in: said'fcircuitnmeans for energizing. said circuit fromsaid source at said first relay, afilter permitting the; flowof 180- '14s 1 said oflice tocontrol said control relay, a nori---;

alternating current bridging said control relay and contact, and means for introducing alternating current into said circuit at said trafiic controlling device under other trafiic conditions to effect energization of said second relay.

3. In a traffic controlling system, the combination with a distant traffic controlling device, of a local central ofice, a source of direct current at said oflice, a circuit connecting said oflice and said distant traffic controlling device for controlling said device through the medium of said source, a first direct current relay at said oflice included in said circuit, a transformer bridged across said relay, a second direct current relay, a rectifier connected to rectify alternating current supplied by said transformer and apply the rectified current to said second relay, a control relay at-said traffic controlling device included in said circuit, means for energizing said circuit from said source at said ofiice to control said control relay, a normally closed traffic controlled contact adjacent said control relay in said circuit opened under certain trafiic conditions to effect de-energization of said first relay, a filter permitting the flow of alternating current bridging said control relay and contact, and means for inducing alternating current into said circuit at said traffic controlling device under other trafiic conditions to effect energization of said second relay, said bridge including the transformer, and said filter bridging said relay and contact, each constituting a unit tuned to resonance at the frequency of said alternating current.

ERNEST B. KEMPSTER, JR. DONALD W. MERSEREAU. 

